A professor teaching at a correspondence school discovers that a Nazi agent is trying to prevent a trade treaty being signed between England and South America.
Prof. Davis
Bobby Jessop
Costello
Crabtree
Joyce
Prof. Davys
Harman
Innsbach
Sir John
Onslowe
Matron
Sister Spooner
B.B.C. Interviewer
Male Nurse
Station Master
Ticket Collector
Sister at Nursing Home
Hotel Receptionist
B.B.C. Producer
Hospital Nurse
Butcher's Boy
Miss Rudge
Journalist
Train Passenger
Mrs. Webster
Ministry Receptionist
Nurse
Porter
